diff --git a/applications/lofar2/libraries/sdp/src/vhdl/node_sdp_filterbank.vhd b/applications/lofar2/libraries/sdp/src/vhdl/node_sdp_filterbank.vhd
index b3135b0faed987692454dfb88f74e1419f79446e..a5fc3cbb82543baaacbe1fe7586e241838b42d50 100644
--- a/applications/lofar2/libraries/sdp/src/vhdl/node_sdp_filterbank.vhd
+++ b/applications/lofar2/libraries/sdp/src/vhdl/node_sdp_filterbank.vhd
@@ -21,9 +21,16 @@
 -------------------------------------------------------------------------------
 --
 -- Author: R. van der Walle
--- Purpose: .
+-- Purpose: 
+-- . Implements the functionality of the subband filterbank (Fsub) in the 
+--   LOFAR2 SDPFW design.
 -- Description:
--- .  
+-- . The subband filterbank seperates the incoming timestamped ADC samples into
+--   512 frequency bands called subbands. 
+-- . It implements a critically sampled poly-phase filterbank (PFB). The PFB consists of a 
+--   poly-phase finite impulse response (PFIR) filter per real input and a 
+--   complex fast fourier transform (FFT) per 2 real inputs. 
+-- . The number of points of the FFT is 1024.
 -- Remark:
 -- .
 -------------------------------------------------------------------------------